Air quality sensor and data acquisition apparatus

ABSTRACT

An air sampling system is configured to detect an air quality metric for a plurality of regions. The sampling system comprises an air sample unit and an air sensor in fluid communication with a sensor supply line and configured to measure the air quality metric. A controller is configured to control the air sample unit to selectively direct a selected sample of a plurality of air samples to the sensor supply line. The controller is further configured to control the air sample unit to direct the remaining air samples to a sample purge line bypassing the sensor supply line. The controller is further configured to change the selected sample over time among the plurality of air samples such that the air quality metric is identified for the plurality of regions.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 15/819,632 filed Nov. 21, 2017, entitled AIR QUALITY SENSOR AND DATA ACQUISITION APPARATUS, now U.S. Pat. No. 10,563,886, which claimed priority to and the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 62/522,159, filed on Jun. 20, 2017, entitled AIR QUALITY SENSOR AND DATA ACQUISITION APPARATUS, the entire disclosures of which are hereby incorporated by reference.

TECHNOLOGICAL FIELD

The present disclosure generally relates to air monitoring systems and, more particularly, relates to air monitoring systems utilizing multipoint air sampling.

BACKGROUND OF THE DISCLOSURE

Building air supply and control systems are becoming increasingly important due to increases in energy cost. In various building ventilation systems (e.g. HVAC systems), it may be beneficial to improve data acquisition for each room of the building. The disclosure provides for a variety of improvements in air sampling and air quality control for building ventilation and control systems.

BRIEF SUMMARY

According to one aspect of the present disclosure, an air sampling system configured to detect an air quality metric for a plurality of regions is disclosed. The sampling system comprises an air sample unit configured to independently transfer air from the plurality of regions as a plurality of air samples. The system further comprises an air sensor in fluid communication with a sensor supply line and configured to measure the air quality metric. A controller is configured to control the air sample unit to selectively direct a selected sample of the plurality of air samples to the sensor supply line. The controller is further configured to control the air sample unit to direct the remaining air samples to a sample purge line bypassing the sensor supply line. The remaining air samples are directed to the sample purge line in coordination with the selected sample being directed to the sensor supply line, such that the remaining samples are concurrently drawn to the air sample unit. The controller is further configured to change the selected sample over time among the plurality of air samples, such that the air quality metric is identified for the plurality of regions and receive an indication of the air quality metric of the selected sample from the air sensor.

According to another aspect of the present disclosure, a method for detecting air quality for a plurality of volumetric regions is disclosed. The method comprises transferring air from a plurality of regions of a building as a plurality of air samples and controlling an air sample unit to selectively direct a selected sample of the plurality of air samples to a sensor supply line. In response to the selected sample directed to the sensor supply line, the method further comprises controlling the air sample unit to direct at least one remaining air sample of the plurality of air samples to a sample purge line bypassing the sensor supply line and detecting an air quality metric for the selected sample supplied to the sensor supply line. The method further comprises changing the selected sample over time among the plurality of air samples, such that the air quality metric is identified for the plurality of regions. The controlling of the air sample unit to direct the at least one remaining air sample to the sample purge line supplies updated air samples from each of the plurality of regions to the air sample unit in coordination with the selected sample being directed to the sensor supply line.

According to yet another aspect of the present disclosure, an air sampling apparatus configured to detect an air quality metric for a plurality of regions is disclosed. The apparatus comprises an air sample unit configured to receive a plurality of air samples from the plurality of regions. The plurality of air samples comprise a selected sample and at least one remaining sample, and the air sample unit is configured to direct the at least one remaining air sample to a sample purge line in coordination with the selected sample being directed to a sensor supply line. The apparatus further comprises an air quality sensor in fluid communication with the sensor supply line and configured to measure the air quality metric. A controller is configured to control the air sample unit to selectively direct the selected sample of the plurality of air samples to the sensor supply line. The controller is further configured to control the air sample unit to direct the at least one remaining air sample to the sample purge line bypassing the sensor supply line in response to the selected sample directed to the sensor supply line. The controller is further configured to change the selected sample over time among the plurality of air samples, such that the air quality metric is identified for the plurality of regions and receive an indication of the air quality metric of the selected sample from the air quality sensor.

These and other aspects, objects, and features of the present disclosure will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings. It will also be understood that features of each embodiment disclosed herein may be used in conjunction with, or as a replacement for, features of the other embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a block diagram of a building demonstrating a plurality of rooms incorporating an air sampling system;

FIG. 2 is a block diagram of a building having an air sampling system;

FIG. 3 is a schematic diagram of the air sampling system; and

FIG. 4 is a detailed schematic diagram of the sample return unit of the air sampling system in accordance with the disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

The present illustrated embodiments reside primarily in combinations of method steps and apparatus components related to an air monitoring device. Accordingly, the apparatus components and method steps have been represented, where appropriate, by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Further, like numerals in the description and drawings represent like elements.

In this document, relational terms, such as first and second, top and bottom, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

Modern heating, ventilation, and air conditioning (HVAC) systems may provide for independent control of various regions or rooms within a building. In this way, climate control and air quality may be monitored and controlled for each region or room. In addition to the benefits of improved comfort and air quality, systems may also be configured to reduce energy consumption. In some cases, conserving energy may include determining occupancy of each room or region. In response to the occupancy or level of occupancy, the HVAC setting may be optimized to ensure that the air quality is maintained. However, there are a variety of challenges that may be associated with implementing such systems on a large scale while maintaining economical HVAC control solutions. The following detailed description provides for a system and control method for an air sampling system that is both effective and economical.

Referring to FIGS. 1 and 2, block diagrams of a building 10 having an air sampling system 100 are shown. The air sampling system 100 may be configured to selectively measure at least one air quality characteristic from a plurality of areas of the building 10. For example, the system 100 may be configured to monitor various volumetric regions of a single room and/or monitor the conditions of each of a plurality of rooms 102 (e.g. rooms 11-14, 21-24, 51-54, etc.). The plurality of rooms 102 or areas of the building 10 may correspond to regions or volumetric spaces within a commercial building, residential building, multi-purpose building, etc. The disclosure may provide for various novel aspects configured to limit the installation and operating cost of the system 100, and may also provide for improved operational performance.

In an exemplary embodiment, the system 100 may comprise an air sampling device 104. The air sampling device 104 may correspond to a scalable monitoring device configured to sample the air from each of the plurality of rooms 102 via an air flow controller 106. The air flow controller 106 may comprise a header configured to receive multiple inputs corresponding to each of the plurality of rooms 102. The air flow controller 106 may be configured to selectively direct a room air sample from a selected room 108 (e.g. room 12) to one or more sensors 110. While drawing the room air sample from the selected room 108, the air sampling device 104 may be configured to draw air from the idle rooms 112 of the plurality of rooms 102. In this configuration, the sampling device may be operable to monitor a condition of the air in each of the plurality of rooms 102 with only limited and consistent delay to gather a current air sample. As will be discussed further herein, the delay of the air sampling device 104 to update a sample for each selected room may be consistent regardless of a distance of the selected room 108 from the sensor 110 of the sampling device 104.

The system 100 may further comprise an air transport motivator or sample return unit 114. The sample return unit 114 may correspond to an energy efficient air transport unit configured to function without a need for direct electrical power. In such embodiments, the sample return unit 114 may be configured to generate suction to draw the room air samples from each of the plurality of rooms 102 via a bulk supply fan of an existing heating, ventilation, and air conditioning (HVAC) system 116 of the building 10. For example, the sample return unit 114 may correspond to a Venturi vacuum device configured to utilize differential pressure derived from the bulk supply fan of the HVAC system 116. Further details of the sample return unit 114 are discussed in reference to FIG. 3. The HVAC system 116 may be configured to provide heating, ventilation, and air conditioning to each of the rooms 102. In this configuration, the sampling return unit 114 may be configured to function without a direct supply of electrical energy.

Though the sample return unit 114 is described in the exemplary embodiment as a Venturi vacuum device, in some embodiments, the sample return unit 114 may recover the room air samples utilizing conventional vacuum pumps or fans. For example, in some embodiments, the sample return unit 114 may utilize suction created via a reciprocating pump, screw or turbine compressor, or various devices configured to displace air in response to receiving electrical current. Such devices may be utilized to provide vacuum pressure to return the room air samples. However, these devices may be noisy, inefficient, and require more maintenance than the Venturi vacuum device disclosed herein.

In the exemplary embodiment utilizing the Venturi vacuum device, the only energy usage of the sample return unit 114 may be a small parasitic energy drawn from the bulk supply fan of the HVAC system 116. For example, the bulk supply fan may consume a small and potentially negligible increased power due to the energy usage of the sample return unit 114. The change in power usage may particularly be negligible when the air sampling system 100 is implemented in large buildings having multiple rooms and high volume HVAC systems 116. In this way, the air sampling system 100 may improve efficiency while limiting components and related maintenance that may be required when utilizing active devices to provide vacuum pressure to return the room air samples. As disclosed, the sample return unit 114 may utilize the existing fluid pressure from the HVAC system 116 to power the sample return unit 114 via the Venturi effect to improve efficiency and limit maintenance.

In operation, the sample return unit 114 may draw room air samples from each of the plurality of rooms 102 perpetually during operation of the bulk supply fan of the HVAC system 116. For example, the controller 120 of the air sampling system 100 may be configured to control the air flow controller 106 to direct a room air sample of a selected room 108 to a quality sensor of the at least one sensor 110 to measure a condition or quality parameter of the selected room 108. The quality sensor is identified as element 140 in FIG. 3 and is discussed further in reference to FIG. 3. Additionally, the air flow controller 106 may be configured to retrieve and purge room air samples 132 from each of the idle rooms 112 (e.g. rooms 11, 13, 14, and 21-24).

By continuously drawing the room air samples from each of the idle rooms 112 and the selected room 108, the air sampling system 100 may continuously supply updated air samples to the air flow controller 106. In this way, the system 100 may supply air samples from each of the rooms 102 to a central location of the air flow controller 106 and selectively direct the air sample from the selected room 108 to the quality sensor 140. Accordingly, the system 100 may avoid delays in updating the air samples from each of the idle rooms 112 that may otherwise be required to purge an associated length of the supply line 122 from each of the rooms 102 to the air flow controller 106. By continuously supplying updated air samples from each of the rooms 102 containing air that is representative of a current air quality, the sampling system 100 is operable to test each of the rooms 102 without significant delay that may otherwise be required to purge air samples. Accordingly, the air supplied from the air flow controller 106 to the at least one sensor 110 may only need to be purged from the air in the sensor supply line 124 rather than each of the air sample supply lines 122 when changing the selected room 108 among the plurality of rooms 102.

In operation, the controller 120 may measure the air quality of one or more of the rooms 102 by cycling the selected room 108 to supply an air sample from one or more of the rooms 102. For example, during such an operation, the controller 120 may control the air flow controller 106 and the at least one sensor 110 to measure the air quality of room 12. Following the measurement of the air quality in room 12, the controller 120 may generate a control signal configured to change the air flow controller 106 to select room 22 as the selected room 108. In this configuration, the idle rooms 112 may include rooms 11-14, 21, 23, and 24; the air samples from these rooms may be purged while the selected room 108 is designated as room 22.

The room air sample from room 22 may be directed by the air flow controller 106 such that the air entering the at least one sensor 110 is from room 22. The controller 120 may then allow a predetermined period of time for the room air sample from room 12 to purge from a sensor supply line 124 and to allow time for a change in the sampled air to become stable in the sensor 110. Once the predetermined period of time has lapsed, the controller 120 may monitor the at least one sensor 110 to identify a condition or quality parameter of the room air sample for room 22. If the room air samples from each of the rooms 102 were not delivered to the air flow controller 106 throughout operation, the purge time may increase dramatically and vary for each of the rooms 102 due to variations in the lengths of the air sample supply lines 122. Such variations and increases in purge time may result in delayed correction of air quality in each of the rooms 102 as well as increased maintenance and operational cost for the sampling system 100.

The controller 120 of the air sampling system 100 may continue to control the air flow controller 106 to test the condition or an air quality parameter of each of the rooms 102 in any sequence. The controller 120 may be configured to monitor each of the room air samples for each of the rooms 102 for a monitoring period, which may be independently specified for one or more of the rooms 102. Additionally, the air sampling system 100 may be configured to monitor the rooms 102 sequentially or in any order. For example, the controller 120 may be configured to control the air flow controller 106 to monitor a frequently occupied room with a greater frequency than other rooms of the plurality of rooms 102.

As discussed previously, the continuous delivery of the room air samples for each of the rooms 102 by the air flow controller 106 may limit a purging time required to gather a current or updated sample from the selected room 108. Additionally, the continuous delivery of the room air samples may limit a flow rate necessary for the sample return unit 114. In this way, the air sampling system 100 can maintain a low cycle time allowing the controller 120 to monitor the condition or an air quality parameter of each of the rooms 102 over a limited cycle time. The cycle time may correspond to a time required for the controller 120 to measure the condition or an air quality parameter of each of the rooms 102 and may also be referred to as a refresh rate.

Systems that do not utilize continuous delivery of the room air samples may require a significant increase in cycle time to monitor the rooms 102 or an increased flow rate for an air sample return unit. For example, the cycle time may increase due to increased purge time required to receive air sample data representative of the current air quality for a selected room 108. The flow rate of the air samples recovered from each room may be increased to limit the purge time, but such operation may require an air sample return device having increased power consumption, which may reduce operational efficiency and increase the noise of operation. Accordingly, the systems and methods disclosed provide for the air sampling system 100 to operate with improved efficiency while maintaining a responsive system having a short cycle time.

Referring now to FIG. 3, a schematic diagram of the air sampling system 100 is shown. As illustrated in FIG. 3, the air flow controller 106, the at least one sensor 110, and the sample return unit 114 are demonstrated in further detail. The air flow controller 106 may comprise a multi-input header 130 configured to receive each of a plurality of room air samples 132 from the plurality of rooms 102. The controller 120 may be configured to output a control signal to control the air flow controller 106 identifying a room of the plurality of rooms 102 to be measured for an air quality parameter or air condition. In response to receiving the signal, the air flow controller 106 may control one or more valves to direct the room air sample from the selected room 108 to the at least one sensor 110. In this way, the room air sample from the selected room 108 may be directed to the at least one sensor 110.

During operation, the room air samples 132 from each of the plurality of rooms 102 may be consistently delivered to the air flow controller 106 via the air sample supply lines 122, each of which is in fluid communication with the air in one of the plurality of rooms 102. The room air samples 132 may be delivered at a rate of a volumetric displacement of air induced by a pressure differential generated in the sample return unit 114. The room air sample from the selected room 108 may be delivered to the at least one sensor 110. From the at least one sensor 110, the air may be drawn into the sample return unit 114 via a coupler 134. Concurrently to the delivery of the room air sample from the selected room 108, the room air samples from the idle rooms 112 may be drawn through the air flow controller 106 to the sample return unit 114 via the coupler 134. In this configuration, the room air samples 132 from each of the plurality of rooms 102 may be consistently delivered to the air flow controller 106 to provide updated room air samples for each of the plurality of rooms 102 throughout operation.

The at least one sensor 110 may correspond to a variety of types of sensors configured to measure one or more properties or air quality parameters of the room air samples 132. In some embodiments, the at least one sensor 110 may correspond to one or more air quality sensors 140 configured to detect a condition or change in condition in each of the room air samples 132. The air quality sensor 140 may be configured to communicate one or more measurements or other data to the controller 120. The controller 120 may process the one or more measurements or other data to identify air quality conditions or metrics for each of the plurality of rooms 102.

The measurements communicated to the controller 120 may be utilized to determine an appropriate action to improve the air quality for a specific room of the plurality of rooms 102. In this way, the controller 120 may identify a condition or change in condition in one or more air quality parameters. Based on the identified condition or change, the controller 120 may communicate a ventilation control signal configured to induce a building management system (BMS) 142 to take corrective action. In response to the ventilation control signal, the BMS 142 may control the HVAC system 116 to provide ventilation, heat, and/or cooled air to a specific room or group of rooms of the plurality of rooms 102.

In an exemplary embodiment, the quality sensor 140 may correspond to a carbon dioxide (CO₂) sensor. The CO₂ sensor may be configured to measure a CO₂ level of the air in the selected room 108. In such an embodiment, the quality sensor 140 (e.g. the CO₂ sensor) may be configured to communicate the CO₂ level of the selected room 108 to the controller 120. Based on a change or measurement of the CO₂ level, the controller 120 may communicate a ventilation control signal to the BMS 142. Based on the ventilation control signal, the BMS 142 may control the HVAC system 116 to provide ventilation, heating, or cooling to the selected room 108 (e.g. room 12). In this way, the system 100 may be configured to monitor the air quality of each of the rooms 102 and communicate the CO₂ level to the building management system 142. Accordingly, the system 100 may be utilized to determine if the ventilation supplied by the HVAC system 116 is sufficient to control the CO₂ level in each of the rooms and communicate the CO₂ level or a representative control signal to the building management system 142 such that the CO₂ level in each of the rooms 102 may be maintained by the building management system 142 within a desired operating range.

Throughout operation, the controller 120 may continue to inspect the room air samples from each of the rooms 102 by controlling the air flow controller 106 to cycle each of the plurality of rooms 102 as the selected room 108. For example, after the controller 120 has received the air quality parameter or measurement from the quality sensor 140 for a first room (e.g. room 12), the controller 120 may output a signal configured to control the air flow controller 106 to deliver a room air sample from a second room (e.g. room 22) to the quality sensor 140. The room air sample for the second room (e.g. room 22) may be measured by the quality sensor 140, which may communicate an air quality parameter to the controller 120. Based on the air quality parameter from the second room (e.g. room 22), the controller 120 may communicate a ventilation control signal to the building management system 142. In response to the ventilation control signal, the building management system 142 may control a ventilation, heating, and/or cooling property of the air supplied to the second room (e.g. room 22). In this way, the air sampling device 104 may provide control information and/or measurement information configured to identify an air quality parameter of the each of the plurality of rooms 102.

Though discussed in reference to the CO₂ sensor, the air quality sensor 140 may correspond to any form of device configured to measure a condition or an air quality parameter of an air sample. For example, the air quality sensor 140 may correspond to one or more forms of volatile organic compound (VOC) sensors, humidity sensors, CO₂ sensors, carbon monoxide (CO) sensors, ozone sensors, etc. Accordingly, the air sampling device 104 may be configured to provide various forms of air quality information to the building management system 142. In various embodiments, the controller 120 of the air sampling device 104 may be configured to provide various signals, measurements, and/or control instructions to the building management system 142 to suit a particular application of the air sampling system 100.

The at least one sensor 110 of the system 100 may further comprise an operation sensor 150, which may correspond to an air flow rate sensor, differential pressure transmitter, pressure sensor, etc. The operation sensor 150 may be connected to an inlet line 152 and an outlet line 154 of the quality sensor 140. In this configuration, the operation sensor 150 may be configured to identify if the air flow provided to the quality sensor 140 is sufficient to measure the air quality parameter of the selected room 108. Additionally, the operation sensor 150 may be configured to identify a change in pressure over the operating life or maintenance cycle of the air sampling system 100. For example, the controller 120 may monitor pressure data supplied by the operation sensor 150 to identify a change in pressure over time or a pressure below a predetermined threshold. Such changes in operating pressure may be utilized by the controller 120 to identify a maintenance condition or failure in operation of the air sampling device 104.

Still referring to FIG. 3, the sample return unit 114 may correspond to an air transport motivator. The sample return unit 114 may correspond to an energy efficient air transport unit configured to function without a need for direct electrical power or a dedicated mechanical drive, vacuum or propulsion system. In such embodiments, the sample return unit 114 may be configured to generate suction to draw the room air samples 132 from each of the plurality of rooms 102 in response to being positioned within an air flow of a bulk supply fan 160 or air displacement device of the HVAC system 116. For example, the sample return unit 114 may correspond to a Venturi vacuum device configured to utilize differential pressure from the air flow in the form of a vacuum pump 162 derived from the bulk supply fan 160. The HVAC system 116 may be configured to provide heating, ventilation, and/or air conditioning to each of the rooms 102. In this configuration, the air sampling system 100 may be configured to function without a dedicated or air displacement device requiring energy that is not already utilized by operating the HVAC system 116.

Though the sample return unit 114 is described in the exemplary embodiment as a Venturi vacuum device, in some embodiments, the sample return unit 114 may recover the room air samples utilizing conventional vacuum pumps or fans. For example, in some embodiments, the sample return unit 114 may utilize suction created via a reciprocating pump, screw or turbine compressor, or various devices configured to displace air in response to receiving electrical current. Such devices may be utilized to provide vacuum pressure to return the room air samples. However, these devices may be noisy, inefficient, and require more maintenance than the Venturi vacuum device disclosed herein.

As discussed herein, in the exemplary embodiment, the only energy usage of the sample return unit 114 may be a small parasitic energy drawn from the bulk supply fan 160 of the HVAC system 116. For example, the bulk supply fan 160 may consume a small and potentially negligible increase in power to provide the suction necessary to operate the sample return unit 114. In this way, the air sampling system 100 may improve efficiency while limiting components and related maintenance that may be required when utilizing active devices to provide vacuum pressure to return the room air samples. Instead, the sample return unit 114 may utilize the existing fluid pressure from the HVAC system 116 to generate suction to power the sample return unit 114 via the Venturi effect to improve efficiency and limit maintenance.

In operation, the sample return unit 114 may draw room air samples from each of the plurality of rooms 102 perpetually during operation of the bulk supply fan 160 of the HVAC system 116. For example, the controller 120 of the air sampling system 100 may be configured to control the air flow controller 106 to direct a room air sample of a selected room 108 (e.g. room 12) to the quality sensor 140. The quality sensor 140 may then measure a condition or quality parameter of the selected room 108. Additionally, the air flow controller 106 may be configured to retrieve and purge room air samples 132 from each of the idle rooms 112 (e.g. rooms 11, 13, 14, and 21-24). By continuously drawing the room air samples 132 from each of the idle rooms 112 and the selected room 108, the air sampling system 100 may supply updated air samples to the air flow controller 106 without significant delay due to purging air samples. Accordingly, the air supplied to the at least one sensor 110 may only need to be purged of the air in the sensor supply line 124 when changing the selected room 108 among the plurality of rooms 102. In this way, the system may provide for economical monitoring of the air quality in each of the rooms 102 while maintaining a low cycle time for monitoring each of the rooms 102. Accordingly, the disclosure provides for a responsive monitoring system operable to quickly and effectively provide control information to a building management system 142 to ensure that room air quality is maintained throughout a building while limiting associated cost and maintenance fees.

Referring to FIG. 4, a detailed schematic diagram sample return unit 114 of the air sampling device 104 is shown. As previously discussed, the sample return unit 114 may comprise the vacuum pump 162 configured to derive suction to draw the air samples from each of the plurality of rooms 102 to the air flow controller 106. The sample return unit 114 or air supply unit of the system 100 may be disposed in an air flow generated by an air supply unit or the bulk fan supply 160 of the HVAC system 116. The sample return unit 114 comprises an air inlet 172 and an air outlet 174. The air inlet 172 is configured to receive an inlet portion 176 a of the air flow 176 and an outlet portion 176 b released through the air outlet 174.

The inlet portion 176 a of the air flow 176 may have an inlet pressure and an inlet velocity. The outlet portion 176 b of the air flow 176 may have an outlet pressure and an outlet velocity. The sample return unit 114 may generate the suction of a suction line 178 by utilizing a pressure differential between the inlet pressure and a vacuum pressure in a vacuum section 182. For example, the pressure differential may be generated by the sample return unit 114 due to the Venturi effect causing the inlet pressure to be greater than a vacuum pressure in the vacuum section 182 between the inlet portion 176 a and the outlet portion 176 b. Additionally, the Venturi effect may cause the inlet velocity to be lower than an intermediate velocity between the inlet portion 176 a and the outlet portion 176 b. In this configuration, the difference between the inlet pressure and the vacuum pressure created by the sample return unit 114 generates the suction that draws the room air samples via the vacuum pump 162 between the air inlet 172 and the air outlet 174.

As previously discussed, the vacuum section 182 is disposed between the air inlet 172 and the air outlet 174. The vacuum section 182 forms a central cross-section perpendicular to the air flow 176. The central cross-section is smaller than an inlet cross-section of the air inlet 172 and an outlet cross-section of the air outlet 174. In this configuration, the changes in the cross-sections among the air inlet 172, the vacuum section 182, and the air outlet 174 may result in vacuum pressure to be generated at the connection between the suction line 178 and the vacuum section 182. In this configuration, the sample return unit 114 may draw the air samples from each of the plurality of rooms 102 to the air flow controller 106. Accordingly, the air samples may be drawn from the plurality of rooms 102 throughout the operation of the air sampling system 100 in response to the activation of the air flow generated by the bulk fan supply 160 of the HVAC system 116.

It will be appreciated that embodiments of the disclosure described herein may be comprised of one or more conventional processors and unique stored program instructions that control one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of an image sensor system and method thereof, as described herein. The non-processor circuits may include, but are not limited to, signal drivers, clock circuits, power source circuits, and/or user input devices. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of the functions are implemented as custom logic. Of course, a combination of the two approaches could be used. Thus, the methods and means for these functions have been described herein. Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation.

It should be appreciated by those skilled in the art that the above described components may be combined in additional or alternative ways not explicitly described herein. Modifications of the various implementations of the disclosure will occur to those skilled in the art and to those who apply the teachings of the disclosure. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of the disclosure, which is defined by the following claims as interpreted according to the principles of patent law, including the Doctrine of Equivalents. 

What is claimed is:
 1. An air sampling system configured to detect an air quality metric for a plurality of regions, the system comprising: an air sample unit configured to independently transfer air from the plurality of regions as a plurality of air samples; an air sensor in fluid communication with a sensor supply line and configured to measure the air quality metric; a controller configured to: control the air sample unit to selectively direct a selected sample of the plurality of air samples to the sensor supply line; control the air sample unit to direct the remaining air samples to a sample purge line bypassing the sensor supply line, wherein the remaining air samples are directed to the sample purge line in coordination with the selected sample being directed to the sensor supply line such that the remaining samples are concurrently drawn to the air sample unit; change the selected sample over time among the plurality of air samples such that the air quality metric is identified for the plurality of regions; and receive an indication of the air quality metric of the selected sample from the air sensor.
 2. The air sampling system according to claim 1, further comprising: an air flow sensor in communication with the controller and configured to monitor air flow to the air sensor.
 3. The air sampling system according to claim 2, wherein the controller is further configured to: receive an air flow signal from the air flow sensor; and identify whether the air flow is sufficient to measure the air quality metric based on the air flow.
 4. The air sampling system according to claim 2, wherein the air flow sensor comprises a pressure differential sensor.
 5. The air sampling system according to claim 4, wherein the pressure differential sensor is configured to measure a pressure differential between an inlet and an outlet of the sensor supply line.
 6. The air sampling system according to claim 4, wherein the inlet and the outlet are positioned on opposing sides of the air sensor.
 7. The air sampling system according to claim 2, wherein the air sample unit comprises a Venturi vacuum device configured to induce the air flow to the sensor supply line and the sample purge line.
 8. The air sampling system according to claim 1, wherein the direction of the remaining air samples to the sample purge line supplies updated air samples from each of the plurality of regions to the air sample unit in response to the selected sample being directed to the sensor supply line.
 9. The air sampling system according to claim 1, wherein the remaining air samples are the plurality of air samples with the exception of the selected sample.
 10. The air sampling system according to claim 1, wherein the air sensor is configured to measure at least one of a carbon dioxide level, a volatile organic compound (VOC) level, humidity level, a carbon monoxide level, and an ozone level.
 11. A method for detecting air quality for a plurality of volumetric regions, the method comprising: transferring air from a plurality of regions of a building as a plurality of air samples; controlling an air sample unit to selectively direct a selected sample of the plurality of air samples to a sensor supply line; in response to the selected sample directed to the sensor supply line, controlling the air sample unit to direct at least one remaining air sample of the plurality of air samples to a sample purge line bypassing the sensor supply line; detecting an air quality metric for the selected sample supplied to the sensor supply line; and changing the selected sample over time among the plurality of air samples, such that the air quality metric is identified for the plurality of regions, wherein the controlling of the air sample unit to direct the at least one remaining air sample to the sample purge line supplies updated air samples from each of the plurality of regions to the air sample unit in coordination with the selected sample being directed to the sensor supply line.
 12. The method according to claim 11, further comprising: detecting an air flow through the sensor supply line; and identifying whether the air flow is sufficient to measure the air quality metric based on the air flow.
 13. The method according to claim 12, wherein the air flow is detected based on a pressure differential between an inlet and an outlet of the sensor supply line.
 14. The air sampling system according to claim 13, wherein pressure differential is measured on opposing sides of an air quality sensor configured to measure the air quality metric.
 15. The method according to claim 12, further comprising: inducing the air flow for the sensor supply line and the sample purge line via a Venturi vacuum device.
 16. The air sampling system according to claim 11, wherein the air quality metric is a measure of at least one of a carbon dioxide level, a volatile organic compound (VOC) level, humidity level, a carbon monoxide level, and an ozone level.
 17. An air sampling apparatus configured to detect an air quality metric for a plurality of regions, the apparatus comprising: an air sample unit configured to receive a plurality of air samples from the plurality of regions, wherein the plurality of air samples comprise a selected sample and at least one remaining sample and the air sample unit is configured to direct the at least one remaining air sample to a sample purge line in coordination with the selected sample being directed to a sensor supply line; an air quality sensor in fluid communication with the sensor supply line and configured to measure the air quality metric; a controller configured to: control the air sample unit to selectively direct the selected sample of the plurality of air samples to the sensor supply line; control the air sample unit to direct the at least one remaining air sample to the sample purge line bypassing the sensor supply line in response to the selected sample directed to the sensor supply line; change the selected sample over time among the plurality of air samples such that the air quality metric is identified for the plurality of regions; and receive an indication of the air quality metric of the selected sample from the air quality sensor.
 18. The air sampling apparatus according to claim 17, further comprising: an air flow sensor in communication with the controller and configured to monitor air flow to the air quality sensor.
 19. The air sampling apparatus according to claim 18, wherein the controller is further configured to: receive an air flow signal from the air flow sensor; and identify whether the air flow is sufficient to measure the air quality metric based on the air flow.
 20. The air sampling system according to claim 18, wherein the air flow sensor comprises a pressure differential sensor configured to measure a pressure differential across the air quality sensor. 